Why the Spring Grove average is three times its median
The Spring Grove average of 17.48 pCi/L is three times the median of 5.80. A few extreme houses pull the average up: 22.9 percent of tests read 20 or higher and 2.7 percent read 100 or higher, three times the county share of 0.9 percent.
Lead with the median when comparing houses and with the tail when planning. Most Spring Grove houses are moderately above the limit, and a minority are far above it, which is why a single test result in this ZIP code can land anywhere from under 1 to several hundred.
Radon in Spring Grove falls with every floor
Spring Grove basements average 19.89 pCi/L, first floors 8.59, second floors 2.74 and third floors 1.08. A third floor room reads less than a tenth of the basement below it.
| Level tested | Tests | Average pCi/L |
|---|---|---|
| Basement | 2,441 | 19.89 |
| First floor | 276 | 8.59 |
| Slab on grade | 124 | 6.93 |
| Second floor | 70 | 2.74 |
| Third floor | 55 | 1.08 |
The slope is steeper here than the county pattern, where first floors average 5.84 and second floors 5.43. It suggests that in Spring Grove the gas is concentrated at ground contact and thins out quickly upward. That is useful for the person sleeping on the second floor and no comfort for the basement, which most households still use.
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Spring Grove houses started from 35.81 pCi/L before mitigation
Among 301 Spring Grove jobs with a reading before and after, the average before the fan was 35.81 pCi/L and the average after was 1.49. The starting level is well above the roughly 24 recorded for mitigated houses in Red Lion and Stewartstown.
The result of the fan is the same everywhere: a drop to under 2. The difference is how far there was to fall, and it shows that Spring Grove houses that get mitigated are the ones with very high readings rather than borderline ones.
What 399 recorded systems cost in Spring Grove
The DEP record holds 399 mitigation systems under ZIP code 17362 since 1987, about 13 for every 100 recorded tests. Since 2024 the record shows 39 installations at a median of $1,225 and an average of $1,260, close to the York County median of $1,150.
Despite the extreme starting levels, the price is ordinary. The cost record by starting level shows the same flat pattern county wide, and the page on how a radon mitigation system works explains why a standard fan handles a high reading. Of the 399 systems, 34 activated a passive pipe left by the builder.
Common questions about radon in Spring Grove
What is the average radon level in Spring Grove, PA?
The average across 3,003 recorded tests is 17.48 pCi/L, second only to Wrightsville among the seven towns with a page here. The typical house reads 5.80, the median, and 58.6 percent of tests reach 4 pCi/L.
Why is the Spring Grove average so much higher than the median?
A minority of houses read very high. In Spring Grove 2.7 percent of tests read 100 pCi/L or more, three times the county share, which pulls the average far above the typical result of 5.80.
Do upper floors in Spring Grove need testing?
A basement test comes first because it shows the upper bound. Spring Grove readings average 19.89 pCi/L in basements and 2.74 on second floors, so upper rooms are lower, but a bedroom on the first floor averages 8.59.
How much does radon mitigation cost in Spring Grove?
The median across 39 systems recorded since 2024 is $1,225, with an average of $1,260, close to the county median of $1,150. High starting levels do not push the recorded price up.